Effect of coalescence on the grain coarsening during liquid-phase sintering of TaC–TiC–Ni cermets

2000 ◽  
Vol 48 (12) ◽  
pp. 3125-3129 ◽  
Author(s):  
Kyoon Choi ◽  
Jin-Woo Choi ◽  
Doh-Yeon Kim ◽  
Nong M Hwang
2013 ◽  
Vol 45 (3) ◽  
pp. 261-271 ◽  
Author(s):  
B. Randjelovic ◽  
K. Shinagawa ◽  
Z.S. Nikolic

From many experiments with mixtures of small and large grains, it can be concluded that during liquid phase sintering, smaller grains partially dissolve and a solid phase precipitates on the larger grains and grain coarsening occurs. The growth rate can be controlled either by the solid-liquid phase boundary reaction or by diffusion through the liquid phase. The microstructure may change either by larger grains growing during the Ostwald ripening process or by shape accommodation. In this study, two-dimensional mathematical approach for simulation of grain coarsening by grain boundary migration based on a physical and corresponding numerical modeling of liquid phase sintering will be considered. A combined mathematical method of analyzing viscous deformation and solute diffusion in liquid bridge between two grains with different sizes will be proposed. The viscous FE method will be used for calculating meniscus of the liquid bridge, with the interfacial tensions taken into consideration. The FE method for diffusion will be also implemented by using the same mesh as the deformation analysis.


2005 ◽  
Vol 494 ◽  
pp. 387-392 ◽  
Author(s):  
Z.S. Nikolić

The microstructure during liquid phase sintering may change either by larger particles growing during the Ostwald ripening process or by shape accommodation. In this study, simulation of liquid phase sintering based on sub-models for solution-precipitation and grain coarsening will be considered. This paper describes a two-dimensional computer-based simulation method for determination of a qualitative and a quantitative effect of the moving grain boundary on the solid/liquid interface during liquid phase sintering of porous structure.


Author(s):  
J. Drennan ◽  
R.H.J. Hannink ◽  
D.R. Clarke ◽  
T.M. Shaw

Magnesia partially stabilised zirconia (Mg-PSZ) ceramics are renowned for their excellent nechanical properties. These are effected by processing conditions and purity of starting materials. It has been previously shown that small additions of strontia (SrO) have the effect of removing the major contaminant, silica (SiO2).The mechanism by which this occurs is not fully understood but the strontia appears to form a very mobile liquid phase at the grain boundaries. As the sintering reaches the final stages the liquid phase is expelled to the surface of the ceramic. A series of experiments, to examine the behaviour of the liquid grain boundary phase, were designed to produce compositional gradients across the ceramic bodies. To achieve this, changes in both silica content and furnace atmosphere were implemented. Analytical electron microscope techniques were used to monitor the form and composition of the phases developed. This paper describes the results of our investigation and the presentation will discuss the work with reference to liquid phase sintering of ceramics in general.


Author(s):  
Mahesh Chandramouli

Magnetization reversal in sintered Fe-Nd-B, a complex, multiphase material, occurs by nucleation and growth of reverse domains making the isolation of the ferromagnetic Fe14Nd2B grains by other nonmagnetic phases crucial. The magnets used in this study were slightly rich in Nd (in comparison to Fe14Nd2B) to promote the formation of Nd-oxides at multigrain junctions and incorporated Dy80Al20 as a liquid phase sintering addition. Dy has been shown to increase the domain wall energy thus making nucleation more difficult while Al is thought to improve the wettability of the Nd-oxide phases.Bulk polished samples were examined in a JEOL 35CF scanning electron microscope (SEM) operated at 30keV equipped with a Be window energy dispersive spectrometer (EDS) detector in order to determine the phase distribution.


1986 ◽  
Vol 47 (C1) ◽  
pp. C1-441-C1-445
Author(s):  
E. KOSTIĆ ◽  
S. J. KISS ◽  
D. CEROVIĆ

2005 ◽  
Vol 96 (2) ◽  
pp. 141-147 ◽  
Author(s):  
Sung-Min Lee ◽  
Suk-Joong L. Kang

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